Synthesis, reactivity and structures of spirocyclic products derived from octachlorocyclotetraphosphazene: comparison with spirocyclic cyclotriphosphazenes and linear phosphazenes

The reaction of N4P4Cl8 1 with the difunctional reagents 2,2'-methylenebis( 4,6-di-tert-butylphenol) (as its disodium salt) and N,N'-diisopropylpropane -1,3-diamine gave the spirocyclic products 2,2-N4P4{[O-4,6-(t-Bu)(2)C6H2](2 )CH2}Cl-6 4 and 2,2-N4P4[N(i-Pr)CH2CH2CH2N(i-Pr)]Cl-6 5. Further reaction o f 1 with 2 mol equivalents of N,N'-diisopropylpropane-1,3-diamine afforded the novel dispiro derivative 2,2,6,6-N4P4[N(i-Pr)CH2CH2CH2N(i-Pr)](2)Cl-4 6 . Whereas the analogous reaction of N3P3Cl6 2 with the above diamine gave t he monospiro derivative 2,2-N3P3[N(i-Pr)CH2CH2 CH2N(i-Pr)]Cl-4 7 readily, t he reaction of 2 with the diols CH2[4,6-(t-Bu)(2)C6H2OH](2) or CH2(4-Me-6-t -BuC6H2OH)(2) is sluggish. In the case of the latter diol, a product formul ated as N3P3[O-4-Me-6-t-BuC6H2-4-Me-6-t-BuC6H2OH]Cl-5 9 was identified (P-3 1 NMR). The linear phosphazene Cl2P(O)N=PCl3 3, by contrast, reacted with C H2(4-Me-6-t-Bu-C6H2OH)(2) and Et3N to give the cyclic product Cl2P(O)N=P[(O -4-Me-6-t-BuC6H2)(2)CH2]Cl 8. Reaction of the spirocycle 5 with an excess o f MeNH2/Et3N afforded the new bicyclic phosphazene containing a spirocyclic ring N4P4[N(i-Pr)CH2CH2CH2N(i-Pr)](NHMe)(4)(NMe) as a crystalline solid. T he crystal structures of 4.0.5C(4)H(8)Cl(2) and 5-8 have been determined.